US 2008/0200803 A1 discloses a cancer detection and treatment instrument comprising a first conductive plate and a second conductive plate which is opposed to the first conductive plate and has a first opening. A first signal line is disposed between the first conductive plate and the second conductive plate, and one end of a first contact member is exposed through the first opening and another end of the first contact member is connected to the first signal line. A dielectric portion is filled between the first and second conductive plates and the first signal line, and a conductive layer surrounds both side surfaces and a front end surface of the dielectric portion, wherein the surfaces are exposed. The cancer detection and treatment instrument further comprises a monolithic microwave integrated circuit supplying a detection-specific ultrahigh-frequency signal and a detection-specific ultrahigh-frequency power to the first signal line and receiving reflected signals through the first signal line. A digital signal processor receives the reflected signals from the monolithic microwave integrated circuit, analyzes electromagnetic characteristics of the reflected signals, and controls a treatment-specific ultrahigh-frequency power in accordance with the analysis result. The microwave-base detection and treatment of cancer regions may have a reduced accuracy only. For example, also larger parts of healthy tissue may be detected and treated as cancer region.